Structural building panels have long been used to facilitate modular construction of buildings. The use of structural building panels facilitates the rapid construction of buildings because these prefabricated panels reduce on-site construction time, while contributing a high level of precision to the overall building assembly. To increase thermal efficiency of structures constructed from structural building panels, while yielding structurally sound building systems, insulation may be incorporated within the building panels. The incorporation of insulation provides a structural insulated panel, or “SIP.”
Conventional SIPs have a sandwich type structure that is comprised of two skin layers that are bonded to an inner core. For example, FIG. 1 is a schematic partial cross section of a conventional structural insulated panel (SIP) 10, comprising an insulative core 12 having opposing skins 14 and 18, respectively. Such conventional SIPs 10 are made from various materials to achieve specific performance criteria. Common SIP materials include cores 12 that are made from plastic foams such as expanded polystyrene, extruded polystyrene, and urethane foams. The outer skins 14 and/or 18 are typically made from oriented strand board, metal such as steel and aluminum, cement board, or other materials.
Due to cost, weight, and the desired properties, if a metal skin 14 or 18 is used, the thickness of the skin is generally 26 gauge (approximately 0.4826 millimeters or 0.019 inches) or thinner.
SIPs utilizing metal skins 14, 18 can suffer from a number of cosmetic imperfections. One type of imperfection is commonly known as “oil canning” 20, which is a slight variation in the planar surface across the flat areas of structural insulated panels 10. Oil canning 20 is a naturally occurring phenomenon that is inherent in the use of sheet metal as a skin 14, 18, which arises during the manufacture of the sheet metal, and may increase during the manufacture and installation of the SIP 10. Indeed, SIP panel manufacturers, such as PermaTherm Inc., of Monticello, Ga., caution that no SIP 10 can be completely free of oil canning effects 20. This imperfection 20 can occur somewhat randomly and unpredictably throughout the skin surface. Oil canning 20 is typically considered to be an aesthetic issue, and not a structural problem or a defect. Generally, the imperfection 20 is so slight that it can only be detected by viewing the resulting distorted images that reflect off of the skin's surface. While only a slight physical defect, the resulting distorted reflection caused by oil canning 20 is often extremely unpleasant from an aesthetic perspective, as it causes carnival-mirror-like reflections.
Metal skinned SIPs 10 can also suffer from denting 24 or pitting 22. This damage can occur during the manufacturing or installation process, or during regular wear and tear. While these problems do not affect the strength or soundness of such SIPs 10, they often create unpleasant visual effects.
To overcome these otherwise unavoidable cosmetic defects, manufacturers often attempt to mask them, such as by creating a stucco-like embossed texture 30, i.e. actual embossing of the skin 14 and/or 18 itself, or by coating the skin surface with a non-reflective or dull finish 32, to decrease the specular reflectivity of the skin 14 and/or 18. These techniques achieve their goals, by preventing a clear reflected image from forming, thereby preventing a person from detecting the defects.
SIP panel manufacturers also discourage the use of high gloss or reflective surfaces, believing that they are more likely to show dust, fingerprints, and smudges. Instead, diffuse matte surfaces are advertised as being easier to clean, because they are more capable of obscuring these imperfections. For example, if unpainted stainless steel is used as a skin, it is normally brushed or sanded so that the surface produces a diffuse reflection.
It would be advantageous to provide structural insulated panels that provide improved optical characteristics for a wide variety of applications. Such structures, systems and/or processes would provide a substantial technical advance.
It would be further advantageous to provide a structural insulated panels that provide high gloss or reflective skins, without suffering from the cosmetic problems or distractions experienced in conventional SIPs. Such structures, systems and/or processes would provide an additional technical advance.